Abstract: Objective：To evaluate the erosive potential of orange juice modified by calcium. Methods：45 permanent teeth were randomly divided into there groups, and were immersed in orange juice, orange juice modified by calcium（0.4g/l, calcium lactate pentahydrate）, and deionized water respectively for 25 hours. A laser fluorescence system was used to make a quantitative record. Results：The experiment showed that the group of orange juice and orange juice modified by calcium showed significant higher laser fluorescence value than the group of deionized water （P<0.05）. Orange juice modified by calcium showed significant lower laser fluorescence value than orange juice group （P<0.05）. Conclusions：Calcium ion could significantly reduce the erosion potential of orange juice.